As of 2:08 PM 21 March 2017 here the video of the motor is! https://youtu.be/r2rbYOiP4lQ
I will continue to work on improving the motion.
As of July 2017, I broke the motor shaft and cannot 3D print a new one until Late August...
SAFETY FIRST!!! KEEP COMPUTERS AWAY FROM PERMANENT MAGNETS AT ALL TIMES. IF ONE OF THESE MAGNETS COMES WITHIN APPROXIMATELY ONE FOOT OF YOUR COMPUTER, IT MAY JUMP OUT OF YOUR HAND AND COME INTO CONTACT WITH YOUR COMPUTER. CONTACT BETWEEN MAGNETS AND COMPUTERS WILL RESULT IN DESTRUCTION OF THE HARD DISK AND LOSS OF ALL DATA ON YOUR COMPUTER!! SERIOUSLY, THIS HAPPENED TO ME WHILE BUILDING THIS. I HAD TO BUY A NEW COMPUTER.
This is a DCBL Electric Motor. It sounds complicated because it is. These parts can be printed, but it took me about 30 hours of assembly and coding to get every last little detail right.
Read the other sections for assembly instructions. This is going to be me yelling at you about magnet safety again!
BE CAREFUL AROUND NEODYMIUM MAGNETS. THEY ARE DANGEROUS. THEY CAN DESTROY COMPUTER DISKS BY COMING WITHIN SIX INCHES. THEY COULD DESTROY A COMPUTER IN A PACEMAKER. IF TWO MAGNETS COME INTO CONTACT WITH EACH OTHER, YOU WILL PROBABLY NOT BE ABLE TO SEPARATE THEM WITHOUT SPECIAL TOOLS! BE CAREFUL! PLEASE!
Overview and Background
What causes this motor to turn?
All electric motors run function because of Electromagnetism. Electromagnetism is complicated. This could be built in pairs of two because it takes a long time to assemble.
In this lesson, students will be able to learn about magnetism through the construction of a DC Brushless Electric Motor. Students will also learn about circuitry and Arduino C if they choose to follow the same design as I did.
Lesson Plan and Activity
This lesson will be in the PLTW style, with kids individually or in pairs working on developing this system. The instructions for assembly are in the "Assembly" section under Materials Needed.
-Neodymium Magnets (https://goo.gl/6ePA1g has the right dimensions)
-Enameled Copper Wire (28 AWG) (I used goo.gl/zphAXL)
-Thin Ferromagnetic Wire (Iron, Steel, Nickel) OR Iron filings
-3D Printed parts
-Arduino Shift Register
-Lots of wires
-Large Electronics Breadboard
Following printing, the printed parts should be cleaned
The motor "core" (The object with six inverted T-shaped things) will be the hardest part to build. Wrap ONE layer of the ferromagnetic wire around each of the six T-shaped things. Alternatively, you can fill the T's with iron filings. Then, leaving about a three-inch lead, begin wrapping the enameled copper wire around the T-shaped things individually. Each one will take 45-60 minutes to wrap, and is done when the "T" has essentially become a block of copper wire. Leave another 3-inch lead on the other end and cut the wire. Wrap all six of the T's separately. When you have finished winding the wire, build the Arduino circuit and connect everything exactly as I did in the image below. Download my code (goo.gl/sQCfD) to your Arduino circuit.
The Arduino is sending 5-volt pulses through each of the electromagnetic coils on the motor. This causes the coils to form a magnetic field. The magnetic field attracts the North pole of the Neodymium magnets on the shaft, and when the 5-volt pulse moves to the next electromagnet, the motor turns to follow it. This is not a very powerful motor because there is not much ferromagnetic substance on the inside of the electromagnets. Mostly this is just a fun toy for nerds; I calculated my torque to be (very approximately) half of a foot-pound of force. (less than 1/10 newton-meters).
A few more hints and cautions to take
So, in case you missed the rest of my warnings, I did literally destroy my hard drive on my computer with my magnets while making this. It was only a $150 repair, but I lost all of my data and settings.
The magnets (sorry, I promise I don't try to annoy you all with magnet safety warnings) also broke my fingernail when I had one in my hand and the other jumped off of my workbench and crushed my finger.
I found it helpful to tape my fingers while winding the wire, 28 gauge enameled copper wire will really cut into your skin.
If the motor is not spinning and is just vibrating, that's probably because some of your electromagnets were wound the opposite direction. I just switched the wires around on mine until it started spinning instead of vibrating.
- Computer Science
This would be a PLTW style lesson, and students would build this with school supplied materials (listed in the materials section).
Rubric and Assessment
Does it work? How close is it to working?
I would recommend that any motion is classified as an 80-90%, and a spinning motion is 100%
If the circuitry is built and seems sound, and it is not moving for unidentifiable reasons, I would give the students an 80%
There are few descriptions of DCBL motors on the internet, and I mostly used Google Images, as well as the previously listed tesla blog post.
I also reviewed the Wikipedia page on Brushless Electric Motors.
What exactly is a DCBL (Also called a BLDC) motor?
A DCBL motor is similar to a Brushed Electric Motor, except it does not have as much heat loss due to the lack of Brushes. Brushes, in Brushed Electric Motors, change the direction of current thought the motor every 2π/3 radians (120 degrees). This is inefficient, as the brushes spark, releasing lots of heat, every 2π/3 radians. A DCBL motor removes brushes entirely, and instead has a permanent magnet axel usually containing 20+ permanent magnets of alternating polarity. Instead of having Brushes that switch the polarities, a control unit, changes the polarity of coils around the magnets.
Sorry. I don't think that description was very helpful. You can try reading the wikipedia article on DCBL motors here: (https://en.wikipedia.org/wiki/Brushless_DC_electric_motor)
What are DCBL motors used for?
Hybrid Electric Cars.
Basically nothing else.
Because of the unique structure of a DCBL motor, it allows for higher efficiency, something that virtually only matters in battery electric vehicles. Today, all HEV's (hybrid electric vehicles) (such as the Toyota Prius and Chevy Volt) use DCBL motors, while most BEV's (battery electric vehicles) (Tesla Model S, Tesla Model X, GM EV1, Chevy Bolt, Nissan Leaf), use/used Three Phase Induction motors. In a blog post, Tesla admitted that they are not certain which is better, Three Phase Induction or DCBL. They did say that DCBL motors are easier to make, and that's why I chose to make one.
Here is Tesla, Inc.'s article on Induction vs DCBL motors. (https://www.tesla.com/blog/induction-versus-dc-brushless-motors)
A replica of GM's EV1, the first major use of a Three Phase Induction motor. DCBL Motors were previously used in Hybrid-Electric Vehicles
As ugly as priuses are, they car have a simple to build and program Brushless DC Electric Motor
Cost of an equivalent motor
I did a quick search on Amazon for DCBL motors and found that a motor of equivalent size to the one I made would cost about $600.00. That one would probably be a bit more reliable, but I think it's way cooler to make your own thing.
For comparison, I was able to make this motor for less than $100.00.